Review of Techniques to Inoculate Grapevines with Grapevine Fanleaf Virus: Lessons and Perspectives

Abstract

Grapevine fanleaf virus (GFLV) occurs in all major grape-growing regions of the world, causing a severe degeneration of vegetation, reductions in grape yield, and poor-quality harvest. GFLV is transmitted through the soil by the ectoparasitic nematode Xiphinema index. Control of GFLV with agrochemicals to eradicate nematode vectors is not feasible in established vineyards. Several laboratories are examining the development of GFLV-resistant rootstocks as a control strategy. In such programs, screening of large plant populations is a critical step in the identification of GFLV-resistant individuals. Different approaches to inoculate grapevine with GFLV have been used with varying degrees of success. We compared four innoculation techniques: nematode-mediated virus transmission, in vitro micrografting, leaf bombardment with gold particles coated with purified virus or viral RNA, and electroporation of mesophyll protoplasts. This review evaluates the efficacy of these techniques and offers insights on the most appropriate approach to inoculate grapevine plants with GFLV according to specific research goals.